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How do I create an empty array/matrix in NumPy?
...might be best off to keep it in a list until it is finished, and only then convert it into an array.
e.g.
mylist = []
for item in data:
mylist.append(item)
mat = numpy.array(mylist)
item can be a list, an array or any iterable, as long
as each item has the same number of elements.
In this ...
How do I create test and train samples from one dataframe with pandas?
...
scikit learn's train_test_split is a good one.
from sklearn.model_selection import train_test_split
train, test = train_test_split(df, test_size=0.2)
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How do I see all foreign keys to a table or column?
...
For a Table:
SELECT
TABLE_NAME,COLUMN_NAME,CONSTRAINT_NAME, REFERENCED_TABLE_NAME,REFERENCED_COLUMN_NAME
FROM
INFORMATION_SCHEMA.KEY_COLUMN_USAGE
WHERE
REFERENCED_TABLE_SCHEMA = '<database>' AND
REFERENCED_TABLE_NAME = '<...
SQL Server: Filter output of sp_who2
... SPID_1 INT,
REQUESTID INT
)
INSERT INTO @Table EXEC sp_who2
SELECT *
FROM @Table
WHERE ....
And filter on what you require.
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JSON.stringify without quotes on properties?
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So, what you are looking for is basically an object inspector not a JSON converter. JSON format specifies that all properties must be enclosed in double quotes. Hence there will not be JSON converters to do what you want as that is simply not a JSON format.Specs here:
https://developer.mozilla.org...
How do I list all the columns in a table?
...
For Oracle (PL/SQL)
SELECT column_name
FROM user_tab_cols
WHERE table_name = 'myTableName'
For MySQL
SHOW COLUMNS FROM table_name
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How do I autoindent in Netbeans?
...s -> Keymap, then look for the action called "Re-indent current line or selection" and set whatever shortcut you want.
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MVC3 DropDownListFor - a simple example?
...uirements. Now, however, how is MVC FW supposed to map the value that is selected on this drop-down back into the simple string property on my view model?
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SQL Inner-join with 3 tables?
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You can do the following (I guessed on table fields,etc)
SELECT s.studentname
, s.studentid
, s.studentdesc
, h.hallname
FROM students s
INNER JOIN hallprefs hp
on s.studentid = hp.studentid
INNER JOIN halls h
on hp.hallid = h.hallid
Based on your request for ...
How to remove all MySQL tables from the command-line without DROP database permissions? [duplicate]
...tatements to execute it:
SET FOREIGN_KEY_CHECKS = 0;
SET @tables = NULL;
SELECT GROUP_CONCAT('`', table_schema, '`.`', table_name, '`') INTO @tables
FROM information_schema.tables
WHERE table_schema = 'database_name'; -- specify DB name here.
SET @tables = CONCAT('DROP TABLE ', @tables);
PRE...